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Defining the Benefits of New Genotypes

by 5m Editor
5 May 2009, at 12:00am

This study has been prepared by BPEX in order to help producers assess the best genotype for their herd. Trials compared the performance results of progeny from Large White, Hampshire and Pietrain boars at each stage of the production cycle and their carcass characteristics.

The UK pig industry has traditionally used a Large White terminal sire over a Large White × Landrace dam but more recently, there has been increased use of three way crosses with Hampshire or Pietrain boars as the terminal sire.

The attraction of these breeds initially arose because certain sire lines have been associated with increased piglet vigour, improved response to weaning, faster growth rates and lower mortality in all phases; this could suggest that offspring are less susceptible to Post-Weaning Multisystemic Wasting Syndrome (PMWS).

A large-scale study conducted by the Pig Development Centre now provides an independent comparison of the performance of piglets from each of the three breed crosses on the same commercially based research farm and an impartial assessment of the major intrinsic differences between modern sire breeds for the use of British farmers.

Each of the following areas was studied, providing information that can be used in determining appropriate breeding strategies.

Pre-Weaning Performance

For this part of the study, results were obtained for a total of 425 crossbred litters (140 Hampshire type, 145 Large White and 140 Pietrain type).

  • There were few differences between piglets from different sire lines.
  • Sire breed did not affect the number of piglets born per litter, nor the numbers of stillbirths or mummified foetuses.
Hampshire type Large White type Pietrain type P-value
Live born 11.15 11.05 11.27 0.901
  • Piglets of all crosses had similar birth and weaning weights.
Hampshire type Large White type Pietrain type P-value
Average piglet weight after 24 hours (kg) 1.55 1.49 1.56 0.167
Average piglet weight at weaning (kg) 8.1 7.9 8.0 0.499
  • Three breed crosses had higher survival rates during the first 24 hours of life, however, subsequently, there were no significant differences in survival between breeds.
Hampshire type Large White type Pietrain type P-value
Deaths in first 24 hours 0.65 1.1 0.48 <0.001
Deaths 24 hours to weaning 0.71 0.59 0.91 0.117

Weaner Performance

For this part of the study, results were obtained for a total of 708 piglets (234 Hampshire type, 240 Large White type and 234 Pietrain type).

  • Genotype did not affect piglet growth rate in the first two weeks of the experiment or over the whole 20-day trial period
  • However, by the third week, Hampshire-type and Large White-type piglets were growing more rapidly than Pietrain-type piglets
Hampshire type Large White type Pietrain type P-value
Overall live weight gain (g/pig/day) 303 298 289 NS
Week 3 live weight gain (g/pig/day) 457 462 392 <0.001
  • Feed intakes were similar between genotypes throughout but Pietrain types had better feed conversion.
Hampshire type Large White type Pietrain type P-value
Feed conversion ratio 1.15 1.19 1.13 <0.05
  • There was no difference between genotypes in the numbers of pigs that were recorded as sick, scouring or lame during the trial.
  • There were no differences in lysine requirement between breeds.

Grower Performance

For this part of the study results were obtained for a total of 894 pigs (306 Hampshire type, 268 Large White type and 320 Pietrain type).

  • Hampshire type pigs grew more rapidly than either of the other two crosses due to greater feed intake
Hampshire type Large White type Pietrain type P-value
Growth rate (g/day) 677 632 645 0.020
  • Although Large White type pigs had the lowest feed intake and growth rate, they had the best feed efficiency.
Hampshire type Large White type Pietrain type P-value
FCR 1.70 1.61 1.64 0.092

The three breed crosses were more robust.

Hampshire type Large White type Pietrain type P-value
Sick (%) 0.73 3.70 0.67 0.013
  • There were no differences in lysine requirement between breeds, with all three genotypes responding similarly to changing lysine concentration.
  • Optimum performance was achieved at lysine concentrations above 1.07g digestible lysine per megajoule (MJ) net energy (NE).

Finisher Performance

For this part of the study, results were obtained for a total of 990 pigs (320 Hampshire type, 340 Large White type, 330 Pietrain type).

Hampshire type Large White type Pietrain type P-value
Growth rate (g/day) 765 723 710 <0.001
Age at average slaughter weight of 102.3 kg (days) 164.8a 172.3b 173.6b <0.001
  • Large White type pigs had the lowest feed intake but best feed efficiency.
Hampshire type Large White type Pietrain type P-value
FCR 2.62 2.40 2.51 0.004
  • The Pietrain and Hampshire type pigs were more robust than the Large White type pigs with half as many pigs having to be removed from the trial.
Hampshire type Large White type Pietrain type P-value
Off trial (per cent) 4.4 8.5 4.9 0.116
  • There were no differences in lysine requirement between breeds, with all three genotypes responding similarly to changing lysine concentration
  • Optimum performance was achieved at lysine concentrations of 0.86g digestible lysine per MJ NE and above

Carcass Composition and Meat Quality

For this part of the study, results were obtained for a total of 1595 pigs (593 Hampshire type, 483 Large White type and 519 Pietrain type).

  • Large White type pigs were leanest as assessed by MLC backfat measurement
  • Pietrain type pigs produced the heaviest carcasses and the greatest yield when assessed on the basis of lean meat yield.
Corrected to a slaughter weight of 102.3 kg Hampshire type Large White type Pietrain type P-value
MLC P2 (mm) 9.96a 9.59b 10.3c <0.001
Lean meat percentage 63.0a 63.9b 64.5c <0.001
  • Although the Hampshire type pigs had the highest daily liveweight gain (P<0.001), in terms of the rate of gain of lean meat (the edible part of the carcase) there was very little difference between the three crossbreeds, however the Pietrain type pigs had the fastest gain and the Large White types the slowest (P=0.019)
  • The muscle from the Pietrain type pigs showed no sign of pale soft exudative (PSE) meat.
  • Pietrain type pigs had significantly thicker ‘eye’ muscles than the Hampshire type pigs
  • The Hampshire type pigs produced the most tender meat (griddled loin steaks) but there were no other significant differences on eating quality between the three crossbreeds.
Hampshire type Large White type Pietrain type P-value
Eye muscle depth (mm) 55.4b 57.5ab 60.6a 0.001
Tenderness (scale 1-8) 4.28 4.06 4.06 0.019
Terminal pH 5.47b 5.55a 5.47b <0.001

Summary

Based on each part of this study, the following characteristics can be attributed to the three breed crosses:

Hampshire types

  • Rapid growth
  • High feed intake
  • Reduced days to slaughter – particularly suitable for attaining higher slaughter weights
  • Robust
  • Tender meat

Large White types

  • Moderate growth
  • Low feed intake
  • Good carcass composition – particularly for conventional payment method
  • Good feed conversion ratio on daily basis

Pietrain types

  • Moderate growth
  • High feed intake
  • Robust
  • Good carcass composition
  • High lean meat yield, especially prime cuts – particularly suitable for outlets interested in better yield or using the autofom

BPEX says that the results from this study can be used to help assess the economic significance of each factor in terms of each producer's own system.

The BPEX Feeding Herd Calculator will allow you to estimate the effects of feed costs and other costs, slaughter weight and sale value on net margins. It will also allow you to change the FCR to match your system.

The BPEX Breeding Herd Calculator allows you to estimate the effects of changes in sow productivity, feed and other costs on the net margin per weaner pig sold on for growing and finishing.

The information from this research should not be used as the sole basis for determining your breeding strategy but in conjunction with discussions with your nutritionist, marketing company and breeding company, advises BPEX.

Further Reading

- Find out more information on Post-Weaning Multisystemic Wasting Syndrome (PMWS) by clicking here.


April 2009